Reddit mentions of Wagner: Der Ring des Nibelungen - Complete Ring Cycle (Levine, Metropolitan Opera)

It seems like people are just naming their favorite composers rather than music similar to Williams. Well, to me Williams sounds the most like Wagner (grand orchestration and leitmotifs) and Bartók (primal rhythms and also a fair bit of the orchestration).

For Wagner, you could start with some overtures, e.g. Lohengrin, Lohengrin act III, Dutchman, Tristan (I guess I'd be remiss if I didn't mention the Liebestod), Parsifal... but those don't really sound that much like John Williams, so sooner or later you'll just have to hunker down and watch the Ring with her. (You'll be surprised at the similarities to Star Wars, and I'm not just talking about the music.) Wagner certainly knows how to "build large-scale works".

Most of Bartók isn't orchestral, but then that wouldn't really sound similar, would it. Popular orchestral works include the five-movement Concerto for Orchestra and four-movement MSPC. If anything, Bartók will sound more like Williams than Wagner does, not because he learned more from Bartók but because his most "distinctive" stuff sounds like Bartók while everyone who ever writes an orchestral film score echoes Wagner.

Once you hear these, you'll realize just how much of a copycat Williams is, but there's nothing wrong with that, and it's hard to fault his choice of source material.

I don't think it was the newer one, but should be whatever year this one was from

I dived in on a tight schedule (my obsessive compulsion prevented me from seeing Siegfried at the Met Live in HD 'cold') so I made a traipse to my uni's music library. They had THIS with ALL THE BOOKLETS. From 8 pm to nearly 2 pm, what I did was read the booklet of the opera, watch the opera, switch DVDs, repeat.

Sans the inherent craziness of watching them straight through, I think watching a subtitled recording would be the best way for you - even better if you can borrow it from someone, or check it out from a library. This particular set had booklets in each DVD with a detailed synopsis, including the original stage directions (as far as I can tell), and this particular production looked like it made an attempt at recreating the imagery, which again seems fitting for what you're looking for.

As an ending to my little tale, apparently, I sucked at reading the calendar, and thus ended up watching Gotterdammerung WHILE SIEGFRIED WAS PLAYING IN THEATRES ;-;.

Aside from actually attending a performance of the cycle (pricey, indeed), this is a great place to start. Rich, faithful staging with wonderful performances.

Since you're looking for a traditional production, I'd say the Met's production conducted by Levine is probably going to be your best bet. I haven't seen a ton of Ring Cycle DVDs, but all of the ones I've seen except for the Met/Levine have been "modern" productions (which can still be pretty cool if you go into it with an open mind). As for English subs, as far as I know most if not all DVDs will have them.